Input pen



FIG. 1 is a front/top/left-side perspective view of an input pen showing my new design;

FIG. 2 is a front elevational view thereof, the rear elevational view being a mirror image and, therefore, not shown;

FIG. 3 is a top plan view thereof;

FIG. 4 is a bottom view thereof;

FIG. 5 is a left-side elevational view thereof; and,

FIG. 6 is a right-side elevational view thereof. 

The ornamental design for input pen, as shown and described. 